Thermostatic controlling mechanism



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M S I N A H C m2 R 2 EG9 v..ml L.. www. AR SMV. .OO BCN .Cd Cle T1 Ai TFs O M R E un T March 6, 1928,

Patented Mar. 6, 1928.

UNITED STATES 1,661,341 PirrEN'r OFFICE.

CHARLES BALDWIN SAWYER, OFGLEVELAND, OHIO, ASSIGNOR TO THRV BRUSH LABORATORIES COMPANY, 0F CLEVELAND, OHIO.v

THERMOSTATIG CONTROLLING MEGHANISI.

Application led November 17, 1922. Serial No. 601,653.

This invention relates to improvements in controlling mechanism and morevparticularly to electric circuit making and breaking mechanismespecially adapted to be 0perated and controlled by thermostatic means,whereby electrical heating means for a chamber or a controller for suchheating.

means shall be accurately controlled in accordance with slighttemperature changes in such chamber and thus accurately maintain asubstantially' constant temperature in said chamber.

One object of my present invention is to provide simple, accurate andefficient mechanism which shall be operable by thermostatic devices, forcontrolling the electric circuit for a heater or the circuit of acontroller for such heater, and thus insure the maintenance of asubstantially constant temerature in a chamber with which said iieatermay be employed. L

A further object is to provide, in a simple and eiiicient structure,circuit controlling mechanism including a magnet cooperable with amovable member of such mechanism to insure quick opening and closing ofan electric circuit whenl said movable member is operated by meansindependently of said magnet, and to so construct such circuitcontrolling mechanism, that the armature of said magnet shall be soconstructed and ar ranged that its motion toward the magnet shallcompress or Hex a spring in opposition to the motion imparted to thearmature by the magnet, so that a stop shall be provided which willdefinitely or positively limit the motion of the armature toward themagnet; and so that a follow-up spring action for one of the contactsshallvbe so provided that as the armature moves away from the magnet,such follow-up spring action will serve to keep the contacts togetheruntil the armature becomes sufficiently removed from the fieldl ofinfluence of the magnet.

With these and other objects in view, the

invention consists in certain novel featur of construction andcombinations of parts as hereinafter set forth and pointed out in theclaims.

In the accompanying drawings;

Figure 1 is a view partly in elevation and partly in section showing anembodiment of my invention;

Figure'2 is an end view, and

Figure 3 is a plan view.

In the embodiment of my invention illustrated in the drawings, I haveshown a base block or plate 1, to the under side of which, the upperedges of metal bellows 2 and 3 are permanently secured by Welding,brazing, soldering or in any other manner to effect an air tightconnection. The bellows 8 is appreciably smaller in diameter than thebellows"` 2 and is located within the latter so that a chamber '4 isformed to contain an expansible liquid,such as benzine, for example. Acylinder 5 of thin `metal and open at its lower end is disposed betweenthe two bellows to prevent possible interlocking of the folds of saidbellows. The base -block or plate 1 is provided with a duct 6 whichcommunicates at one end with the chamber 4 between the bellows and withthe other end of said duct, one end of a tube 7 is connected,-the otherend of said tube having a bulb 8 (preferably ofmetal) connected theretoand intended to be located in a chamber, the temperatureof which is tobe regulated. The bulb 8, tube 7 duct 6 and chamber 4 are completelyfilled with expansible liquid so thatno vapor space will be left in thesystemcomprising these elements,

"and such liquid may be introducedthrough a suitable opening in the bulband such opening then-permanently closed.

The block or plate 1 and the parts carried thereby may be supported on ayoke or frame .9 to which said block or plate may be' suitably secured,and the bottom of the bellows 2 is provided with a depending rod or tube10 which is internally threaded to receive a screw rod 11, the latterhaving swivel connection with the cross bar 9 of the yoke or frame 9 andprovided with a manually operable knob 12. By thus connecting the bottomof the bellows 2 with the yoke or frame, said bellows will be heldnormall v stationary but the screw connection also a fords means wherebysaid bellows may be adjusted 'to alter its capacity. The generalarrangement of the thermostat cartridge and the adjustment mechanismconstitutes the subject matter of my copending application Serial No.601,652, led Nov. 17th, 1922 and entitled Thermostat controllingmechanism.

In the embodiment of my invention shown in the drawings, a lever 13 ispivotally supported at one end by a bracket 14 mounted upon andinsulated from'the block or plate l one oi the latter and this levercarries an adjusting screw 15, the lower end tot which is engaged by theinsulated upper end et apost 16 carried by the movable oit the innerbellows 3.

Ari insulating block 17, securcdto the base plate 1, carries a bindingpost 18, to which i is attached a itlat spring 19, and the latter dlldll

carries a contact point 20,-upward motion oit the spring 19 beinglimited by a stop 21. The movable contact 22 ot the make-andbreahmechanism is carried by thc tree end portion ot a steel spring arm 23secured to and in effect constituting a continuation ot the pivotedlever 13. The contacts and 22 may be connected, in any suitable mannerin circuit with an electric heater or with controlling means tor aheater, but as these details form no part of my present invention theyneed not be shown and described herein 1t may be explained however, thatone circuit wire will be connected with the binding post 13, and theother with a binding post 211 secured to but insulated from the block orplate 1 and connected by a conductor 25 with the bracket 14 to which thelever is pit/cited,

il magnet 26 (preferably of the horseehoe type) may be supported on theend oit the base plate 1, in such position that its poles will be inproximity to the steel spring 23, the latter acting, in etlect, as anarmature 'tor said niagnet,so that when the contact 22 approaches thecontact 20, said spring will come within the lines of force et themagnet and the contacts caused to close quickly, the torce of saidmagnet being suicient to force the spring 19 down against the insulatingblock 17 which arrests the travel ot the spring 23 and prevents it ilromstriking the poles of the magnet 26.y

`lll/hen the upward force of thehead .ot bellows 3, acting throughtlierod or post 16, and pivoted member 13 has flexed spring 23 sudiciently,said spring will leave the magnet 26, but spring 19 will cause contactpoint 20 to follow-up and remain in contact with contact point 22 untilrestrained by the stop 21. F'lhus at the time when the force exerted bytiered spring 23 is almost equal to restraining torce ot magnet 26, thespring 19 holds the Contact points tirmly together and preventsfluttering and consequent de- (titl structive sparking which mightotherwise occur at this time. Furthermore, the spring 19 holds thecontact points together until the spring 23 has definitely left themagnet @.26 and is moving rapidly, so that the circuit is brolzensuddenly and with a minimum of sparking when the stop 21 restrains themotion of contact point 20. Should the contact points 2O and -22 sticktogether, by reason ot an unduly large electric current through them, orfor any other cause, the

pivoted member 13 in conjunction with the meneer spring. member 23 willconstitute a toggle l joint system, actuated near its middle point bypost 16, so that a large torce will bedeveloped tending to slide thecontact points 22-20, one over the other in addition to the normalseparating torce, and in this way break them apart and effect theirseparation. ln normal operation, this toggle joint action is likewisepresent to some entcnt, undvcauses lateral or sliding motion of thecontact points with respect to each other, both on opening and closing",which tends to keep the contact surfaces bright and in good electricalcondition.

The device will be so initially adjusted that when a predeterminedtemperature has been attained inthe chamber, (the temperature ot whichis to be kept constant), the circuit closer will be operated to open thecircuit ot' the heater. Such adjustment is eiiected by adjustingr theposition ot. the head ot the larger bellows 2 by 'means oit theadjusting screw 11. llVhen the head of bellows 2 is lowered, theatmospheric pressure acting on bellows 3 Will extend it saciently tomaintain constant the volume oit space 4 between bellows 2 and 3, sincethis space and the thermostatic system communicating with it iscompletely filled with liquid, without vapor or gas space. Thisextension of bellows 3 will cause 'the contact points to come togetherand close the eleclili tric circuit, and a higher temperature thanbefore will be necessary to cause the circuit to open, but when thistemperature lis reached, the device will operate as before tov maintainthis temperature constant. Conversely, raising the head of the bellows 2by means of the adjusting screw 11 will cause the device to operate' atand maintain constant a lower temperature.,

Having fully described my invention what l claim as new and desire tosecure by Letters-Patent, is

1. lln mechanism of the cliaractei described, the combination of apivoted meniber including a flexible part carrying a con-k tact, .acontact cooperable with said firstinentioned contact, and a meanscooperable with said pivoted member for moving it,

whereby said. member will have a toggle' action to cause the contactcarried thereby to wipe the other contact and also to separate onecontact :trom the other, the connection between the Contact carried bysaid pivoted member and the pivotal mounting therefor beingsubstantially inextensible within the normal range of operation of themechanism.y

2. lin mechanism of the character described, the combination of apivoted lever lill) device having a movable part cooperable with saidlever, and a magnet having cooperative relation to said spring armbetween the contact thereon and said lever, the connection between thecont-act carried by said pivoted member and the pivotal mountingtherefor being substantially inextensible for the normal range ofoperation of the mechanism.

3. In mechanism of the character described, the combination of a pivotedlever provided with a flexible part carrying a contact, another contactfor cooperation with the first-mentioned contact, a magnet operativelyassociated with said flexible part, means operable to limit the movementof said flexible part toward the magnet, and a thermostatic devicecooperable with said lever, the connection between the contact carriedby said pivoted member and the pivotal mounting therefor and theconnection between the second contact member and the mounting of thefollow-up spring therefor each being substantially inextensible.

4. In mechanism of the character described, the combination of a pivotedlever provided with a flexible part carrying a contact, a follow-upspring carrying a contact for cooperation with said first mentionedcontact, a magnet cooperatively associated with the flexible part ofsaid lever, and a thermostatic device having a movable memberoperatively associated with said lever,

the connection between the contact carried by said pivoted member andthe pivotal mounting therefor and the connection between the secondcontact member and the mounting of the follow-up spring therefor eachbeing substantially inextensible.

5. In mechanism ofA the character described, the combination of apivoted lever provided with a flexible part carrying a contact, afollow-up spring carrying a second contact for cooperation with saidVfirst mentioned contact, and a stop for limiting the movement of thefollow-up spring when the first contact carried on the flexible part ofthe lever moves away from the second contact, a magnet cooperativelyassociated with the flexible part of said lever, and a thermostaticdevice having a movable member operatively associated with said lever,the connection between the contact carried by said pivoted member andthe pivotal mounting therefor and the connection between the secondcontact member and the mounting of the follow-up spring therefor eachbeing substantially inextensible.

6. In mechanism of they character described, the combination of a. baseplate, a thermostatic device supported by said base plate, a leverpivotally mounted on said base plate and including a flexible member,connecting means between said lever and a movable part of saidthermostatic device, a contact carried by the flexible member of saidlever, a magnet supported b the base plate and cooperable with saidexible member, an insulating member projecting from said base plate, anda follow-up spring secured to said insulating member and carrying asecond contact cooperable with said firstmentioned contact,`theconnection between` the contact carried by said pivoted member and thepivotal mounting therefor and the connection between the second contactniember and the mounting of the follow-up spring therefor cach beingsubstantially inextensible.

7. In mechanism of the character described, the combination with asupport, and a contact member carried thereby, of a movable contactmember cooperable with the first-mentioned contact member, said movablecontact member including a pivoted arm and a spring arm carried thereby,athermostatic device connected with said pivoted arm, and a magnetcooperable with said spring arm rearwardly of the free end thereof, theconnection between the movable cont-act and the pivot mounting for saidpivot arm being substantially inextensible in the direction of the arm.

8. A sensitively actuated electrical switching mechanism comprising anactuating element capable of exerting relatively great force over smallrange of positive Amovement, a pivotal support, a lever actuated by saidactuating element pivotally mounted on said support, the pivoted portionof said lever being relatively rigid to provide a substantiallynon-*flexing portion between the point of application of the force fromsaid actuating element and the pivotal support for said lever, saidlever also having a flexible portion, an armature carried by theflexible portion of said lever, an electrical contact member carried bythe .flexible portion of said lever` and a second contact member carriedby the support, a magnet adapted to actuate said armature underpredetermined conditions to maintain said contact members in contactingrelation, the non-flexing portion of said pivoted lever being adapted tofollow the movements of ll said actuating element, said lever beingsubstantially inextensible between the pivot mounting and the contactcarrying portion whereby shearing stresses are developed between saidcontact members at the instant 120 before separation when the actuatinmechanism flexes the flexible portion of sald lever and the contactelements remain in engagement.

9. In temperature controlling apparatus 125 the combination with achamber completely filled with liquid and having an expansible portionmovable in response to changes in volume of said liquid, an electriccircuit opening and closing mechanism adapted to lltli be actuated bythe movable. portion of said enclosed chamber, said circuit opening andclosing mechanism comprising a pivotally mounted lever having a portion`adapted to more with the movable portion ot said cnclosed chamber and asecond relatively ilexible portion, a contact member carried by thellexible portion of the lever remote from the pivotal mounting of thelever, and a second contact member adapted to cooperate therewith tocontrol an electric circuit, means adapted to delay the operation of theflexible end portion ot the lever in order that itsoperation may alwaysbe slightly delayed relative to the operation ol the movable portion ofsaid chamber at the instant of separation of said contact members inorder to insure critical operation of the contact members that ismaterially more rapid than the corrosponding movement of the movableportion of the enclosed chamber. Y

l0. An electric circuit controlling mechanism comprising a base, a leverhaving a relatively rigid portion and a flexible portion, a pivotalsupport connecting the relatively rigid portion of said lever to saidbase, an actuating element capable of exerting a relatively great forceover a relatively small range oft movement adapted to actuate therelatively rigid portion of saidlever, a conf tact member carried by theflexible portion of said lever, the lever between the pivotal mountingand the contact member being substantially inextensible over the normalrange ot' operation of the device, and a second contact carried by thebase, means for delayingv the operation ot the lleXible end portion ofthe lever relative to the movement of the actuating element prior toseparation of the contact members to insure critical operation of thecontact members that is materially more rapid than the correspondingmovement vof the actuatingelement, the operation ot said actuatingelement beingl adapted to slightly flex the flexible portion ot saidlever under predetermined conditions When said Contact members remainvin closed position thereby tending to slide one contact member' over theother Contact member at the instant preceding separationto effect apositive release ot said contact members. l1.- An electric switchmechanism, coinneonata prising a lever including a rigid member and aflexible member, a. support with which the rigid portion ot said leveris pivotally eonnected, a Contact member czrried by said support., a`second Contact member carried by the flexible vmember oit said lever andco operable with said first mentioned contact member, a magnetpositioned lor cooperation with the end portion of the lever remote fromits pivotal sipport, and an actuating element including a movable memberengaged byv the rigid member ot the pivoted lever. Y

l2. ilu electric lswitch mechanism, cfomprising a lever including arigid member and 4a flexible member, a support with which-the Y,

rigid portion of said lever is pivotally connected,- a contact memberfarricd by said support, a second contact member carriedby the flexiblemember ot said lever and cooperable with said irst mentioned contactmember, an armature carried by the lever and positioned intern'iediatethe pivotal mounting for the lever andthe Contact member carriedthereby. a magnet cooperating with said armature, and a tlierinostaticactuating element including a movable member adapted to engage the rigidmember of the pivoted lever.

'13. An electric switch mechanism, comprising a lever including a rigidmember and a flexible member, asupport With which the rigid portion ofsaid lever is pivotally connected, a contact vmelnber carried by saidsupport, a second contact member carried by the flexible memberl ot saidlever and cooperable with said first mentioned contact member, theconnection between the pivotal mounting for the lever and the'contactelcment carried thereby being substantially inextensible, an varmaturecarried by the lever and disposed intermediate the first named contactmember andthe pivotal 'mounting for the lever, a magnet positionedforcoop- CHARLES BALDWIN SAWYER.

-eration with said armature, and an actuating

